Returns the number of parents to the specified item in a given PATH result, including self.
|path||A text expression resulting from evaluation of a PATH function.|
The number of items that are parents to the specified item in a given PATH result, including the specified item.
This function is not supported for use in DirectQuery mode when used in calculated columns or row-level security (RLS) rules.
The following example takes an employee ID as input to a PATH function and returns a list of the managers above that employee in the hierarchy, The PATHLENGTH function takes that result and counts the different levels of employees and managers, including the employee you started with.
= PATHLENGTH(PATH(Employee[EmployeeKey], Employee[ParentEmployeeKey]))